Inflatable packer with roughened mandrel

Abstract

An inflatable packer including a tubular mandrel, a pair of collars secured to the mandrel, and an inflatable sleeve connected between the collars about the mandrel. The exterior surface of the mandrel underlying the sleeve is roughened to increase the coefficient of friction between the mandrel and the sleeve.

What is claimed is: 
     
       1. An inflatable packer for use in a well bore comprising: a tubular mandrel constructed of a load supporting steel pipe member, said tubular mandrel having a length of ten feet or more,   an elastomeric tubular sleeve disposed on said tubular mandrel and attached at its ends to said tubular mandrel, said tubular sleeve normally being in contact with the outer surface of said tubular mandrel and being adapted to expand outwardly relative to said tubular mandrel into contact with the wall of a well bore upon the application of a cement slurry fluid upon pressure between said tubular sleeve and said tubular mandrel, and   said steel pipe member having an irregular outer surface configuration along its length providing protrusions along the said outer surface configuration for engagement with the tubular sleeve so that said irregular outer surface configuration provides a substantial coefficient of friction for preventing the tubular sleeve from relative longitudinal displacement relative to the steel pipe member while going in the well bore and so that upon expansion of the tubular sleeve, the cement slurry fluid is in direct contact with the tubular mandrel and the tubular sleeve whereby a cement bond log can be obtained in a well bore through the length of said steel pipe member.   
     
     
       2. The packer as defined in claim 1 wherein said irregular outer surface configuration consists of closely spaced grooves where the depth of the grooves and the height of the projections defining the edges of the grooves are within predetermined diameter tolerances. 
     
     
       3. The inflatable packer as claimed in claim 1, wherein said irregular outer surface configuration is defined by a plurality of first helical grooves formed in the exterior of said stel pipe member and of second helical grooves formed in said exterior of said steel pipe member substantially orthogonal to said first helical grooves. 
     
     
       4. A method of making an inflatable packer for use in a well bore, which comprises the steps of: roughening the exterior surface of a metal tubular mandrel at least ten feet in length along its length;   covering the roughened exterior surface of the metal tubular mandrel with an inflatable elastomer sleeve disposed in frictional contact with the roughened exterior surface for the purpose of preventing relative longitudinal displacement of the inflatable sleeve relative to the tubular mandrel, and for avoiding the use of acoustical inhibiting materials between said sleeve and said tubular mandrel so that in a well bore, a cement bond log can be obtained through the length of said tubular mandrel;   and sealingly connecting the ends of the inflatable sleeve to the tubular mandrel so that the inflatable sleeve may be inflated relative to the tubular mandrel upon the application of a cement slurry fluid under pressure while in a well bore.   
     
     
       5. The method as claimed in claim 4, wherein the roughening step includes the steps of: forming a plurality of first helical grooves in the exterior surface of the tubular mandrel.   
     
     
       6. The method as claimed in claim 5, wherein the roughening step includes the step of: forming a plurality second helical grooves in the exterior surface of the tubular member substantially orthogonal to first helical grooves.